For example, in a product or service (credit) transaction using a credit card, the safety (security) of the transaction is secured by recognizing (personal verification) whether a person who performs the transaction is the same person as the owner of the credit card which is used in the transaction. The personal verification is performed in such a way that a customer signs signature on a transaction statement on which the transaction content is printed when a transaction settlement process is performed, and a clerk compares the signature with the signature signed on the credit card by sight.
In recent years, terminal devices, which can input and display signatures, have been realized using smart phones, tablet terminals, or the like. A plurality of smart phones and the tablet terminals are distributed as consumer devices, and thus it is possible to construct settlement terminal devices by obtaining the smart phones, the tablet terminals, or the like inexpensively. That is, in a case in which it is possible to form the settlement terminal devices using information terminals which are distributed in plural as consumer devices similarly to the smart phones, the tablet terminals, or the like, it is possible to obtain the settlement terminal devices inexpensively. In addition, since a wide use of application (software) development platform which is used in business other than in the settlement process becomes possible, and thus the reuse and distribution of the development resources become easy.
However, information terminals, which are designed to be mainly used as consumer devices, do not have “tamper resistance” which is necessary to safely perform a transaction while protecting customer information. The “tamper resistance” indicates tolerance to attacks that attempt to steal information from the information terminal. In order to secure tamper resistance as a measure to prevent the attacks that attempt to steal information from the information terminal, a mobile device is proposed in which a portion (in PTL 1, referred to as “secured portion”. A portion which has tamper resistance necessary as the settlement terminal device), which is relevant to card authentication information used for the settlement process, is separated from a general-purpose portion (for example, refer to PTLs 1 and 2).